Enhancing and switching spin-valley filtered polarizations in a magnetic WSe2 superlattice induced by Fermi velocity modulation

Abstract

The spin–valley transport is studied in a Fermi velocity-modulated monolayer WSe2 magnetic superlattice. Based on these results, a scheme that can achieve an enhancing and switching spin–valley filter is proposed in the superlattice system. We find the Fermi velocity enhanced and switched spin-valley dependent conductance transport gaps by increasing the number of Fermi velocity barriers, which are verified by the transmission probabilities and Bloch theorem. When compared to a mono-periodic superlattice, the maximum spin ↓ and valley K′ polarized conductance in a well-constructed superlattice structure are greatly improved to a detectable degree. More importantly, the crucial bias voltage or exchange field can dynamically flip and control the valley polarized conductance, something that is not possible in a mono-periodic superlattice. Our findings indicate that a Fermi velocity modulated superlattice structure can be a great way to improve the spin-valley filtered polarizations of devices based on transition metal dichalcogenides.